JP2932875B2 - Method and apparatus for measuring molten metal surface depth in incineration ash melting furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the depth of a slag melt and a metal in a melting furnace for melting waste such as incineration ash and sewage sludge. And an apparatus.

[0002]

2. Description of the Related Art Waste such as incinerated ash of urban garbage and sewage sludge contains various inorganic and organic substances, and if these are buried as they are, serious secondary pollution is caused. In recent years, incineration ash melting furnaces have been used to detoxify such wastes. In this melting furnace, most of the waste is turned into molten slag, which is a vitreous melt, and the remainder is turned into molten metal of metal by resistance heating by applying electricity between the electrodes loaded inside, and the two are separated and externally separated. To be discharged. In order to operate the melting furnace efficiently, it is desirable that a predetermined amount of waste is sequentially charged into the melting furnace, a large amount of molten slag is continuously taken out, and a small amount of molten metal is taken out intermittently. As a condition in this case, it is necessary that the slag surface in the furnace is always kept at a predetermined position so that the height difference between the slag surface of the molten slag and the slag port is always constant.

[0003] By the way, since the upper part of this melting furnace is sealed, the position of the slag surface in the furnace cannot be known. And since the ratio of organic matter and inorganic matter contained in the waste is not known, even if a predetermined amount of waste is put into the melting furnace, the position of the slag surface fluctuates. There is a risk that molten slag may overflow from the furnace when the position of the slag surface is too high because the slag cannot be reused because the slag is clogged or the metal is mixed with the molten slag to be taken out. Further, since the position of the metal surface also fluctuated, it was not possible to judge when to remove the metal. Therefore, in order to avoid such a situation, it is required to know the position of the slag surface in the furnace and adjust the removal of the slag and metal accordingly to make the slag surface constant.

[0004]

Conventionally, in an incineration ash melting furnace having a closed upper part, there has been no method or apparatus for finding the position of the slag surface in the furnace. The present invention
It has been made to solve such a problem, and in a melting furnace in which the upper part is sealed, a method and apparatus for measuring a molten metal surface depth of a melting furnace capable of knowing a position of a slag surface in the furnace. The purpose is to gain.

[0005]

According to the method of measuring the molten metal surface depth of an incineration ash melting furnace according to the present invention, the upper part is closed, and a plurality of electrodes filled in the furnace are heated in the furnace by electric resistance heating. In the method for measuring the molten metal surface depth of an incineration ash melting furnace that melts incinerated ash, a metal wire is fed from the furnace top to a terminal plate provided at the furnace bottom at a predetermined feed rate. Measuring the voltage change between the wire and the terminal plate provided on the furnace bottom caused by the current flowing between the electrodes for electric resistance heating in the molten slag during the wire feeding, and measuring the wire feeding amount and the The positions of the slag surface and the metal surface from the furnace top are calculated and obtained based on the time required for the voltage to change from 0V and the time required for the voltage to change to 0V. The molten metal surface depth measuring device of the incineration ash melting furnace according to the present invention,
The upper part is closed, and the electric resistance heating of a plurality of electrodes filled in the furnace, from the top of the incineration ash melting furnace, which melts the incineration ash charged into the furnace, from the furnace top to the terminal plate provided at the furnace bottom A wire feeder that feeds a metal wire at a predetermined feed rate, an encoder that measures the feed rate of the wire fed by the wire feeder, and the electric current generated by the current flowing between the electrodes for resistance heating. A voltmeter that measures the voltage between the wire and the terminal plate, based on the wire feed amount measured by the encoder and the time until the voltage measured by the voltmeter changes from 0V and the time until the voltage changes to 0V. A calculating means for calculating the positions of the slag surface and the metal surface from the furnace top.

[0006]

In the present invention, a metal wire is fed by a wire feeder from a furnace top of a melting furnace to a terminal plate provided on the furnace bottom at a predetermined feed rate, and the wire feeder is used by an encoder. The voltage between the wire and the terminal plate provided on the furnace bottom caused by the current flowing between the electrodes for electric resistance heating in the molten slag during the wire feeding is measured. The change is measured, and based on the amount of wire feeding measured by the encoder and the time until the voltage measured from the voltage change measured by the voltmeter changes from 0 V and the time until the voltage changes to 0 V, Since the positions of the slag surface and the metal surface from the furnace top are calculated, the positions of the slag surface and the metal surface from the furnace top of the melting furnace can be known from the calculation values of the calculation means.

[0007]

FIG. 1 is a block diagram showing an apparatus for measuring the molten metal surface depth of an incineration ash melting furnace according to an embodiment of the present invention. FIG. 2 is a plan view showing the arrangement of electrodes and wires of the incineration ash melting furnace. 3 is a waveform diagram of the voltmeter of the measuring device when the molten slag is 1400 ° C., and FIG. 4 is a graph showing a relationship between a voltage change of the voltmeter of the measuring device and a wire feeding time. In the figure, 1 is an incineration ash melting furnace
2 is a furnace body of the incineration ash melting furnace 1, 3 is a lid covered on the upper part of the furnace body 2, 4 is vertically movable through the lid 3, and two electrodes whose lower ends reach near the furnace bottom. Reference numeral 5 denotes two incineration ash inlets provided on the lid 2, reference numeral 6 denotes a slag outlet provided on the furnace wall of the furnace main body 2, reference numeral 7 denotes a metal provided at a furnace bottom position of the furnace wall of the furnace main body 2. A hole 8 is a terminal plate provided on the furnace bottom of the furnace body 2.

Reference numeral 10 denotes a metal wire having a diameter of 4.8 mm;
Penetrates the lid 2 from the furnace top of the melting furnace 1 to the terminal plate 8 at the furnace bottom.
And a motor 13 for driving the pair of rollers 12, 12. 14 is an encoder for measuring the feed amount of the metallic wire 10 sent out by the wire feeder 11, 15 is an AC voltmeter for measuring the voltage between the wire 10 and the terminal plate 8, and 16 is the wire feed amount of the encoder 14. And calculating the position of the slag surface and the metal surface from the furnace top based on the time until the voltage measured from the voltage change measured by the AC voltmeter 15 changes from 0V and the time until the voltage changes to 0V. Means 17 is a level indicator for displaying the positions of the slag surface and the metal surface based on the operation value of the operation means 16.

Next, the case where the method of the present invention is carried out using the apparatus for measuring the molten metal surface depth of the incineration ash melting furnace of the above embodiment will be described with reference to FIGS. First, the incineration ash supplied from the incineration ash inlet 5 into the furnace main body 2 is melted by resistance heating generated by the application of an AC voltage between the electrodes 4 and 4 to become molten slag and molten metal. A molten metal layer M is formed. At this time, the terminal plates 4, 4 are held such that their lower ends maintain a certain distance from the surface of the molten slag layer S. Thus, the molten slag layer S
When the molten metal layer M is formed, the wire 10 is fed by the wire feeder 11 from the furnace top of the furnace body 2 toward the terminal plate 8 at the furnace bottom at a predetermined feed rate. At this time, the encoder 14 measures the feed amount of the wire 10 sent out by the wire feeder 11 from the rotation speed of the motor 13. At the same time as the wire 10 is fed, the AC voltmeter 15 measures a voltage change between the wire 10 and the terminal plate 8 caused by a current flowing through the electrodes 4 and 4 in the molten slag layer S. 1
The measurement value of 5 is sent to the calculating means 16. Further, the wire feed amount measured by the encoder 14 is also sent to the calculating means 16. The arithmetic means 16 calculates the time required for the voltage measured from the voltage change measured by the AC voltmeter 15 to change from 0 V, the time required for the voltage to change to 0 V, and the encoder 14.
The positions of the slag surface and the metal surface from the furnace top are calculated based on the wire feed amount. The level indicator 7 is a computing means 16
Of the molten slag layer S from the furnace top of the furnace body 2 according to the calculated value of
Of the slag surface and the metal surface of the molten metal layer M are displayed.

As described above, the calculating means 16 uses the AC voltmeter 1
5, the position of the slag surface and the position of the metal surface can be obtained by calculation from the time until the measured voltage changes from 0 V, the time until the voltage changes to 0 V, and the wire feed amount of the encoder 14. The reason is as follows. FIG. 3 shows that the temperature of the molten slag in the furnace body 2 is 1400.
AC voltmeter 15 accompanying sending out of wire 10
3 shows a voltage change of the first embodiment. As shown in FIG.
When 0 is in the furnace space, the AC voltmeter 15 indicates 0 V,
When the wire 10 reaches the slag surface of the molten slag layer S, it shows 1.7 V, and then the voltage gradually increases, and when it reaches the approximate center position of the molten slag layer S, it shows a maximum of 4 V,
Then, the voltage gradually decreases, and shows 0.7 V immediately before reaching the metal surface of the molten metal layer M, and shows 0 V when it reaches the metal surface. That is, when the voltage between the wire 10 and the terminal plate 8 changes from 0 V, the wire 10
Indicates that the wire 10 is positioned on the metal surface of the molten metal layer M when the voltage changes to 0V.

FIG. 4 shows the relationship between the lapse of the feed time of the wire 10 and the change in the voltage of the AC voltmeter 16 when the temperature of the molten slag in the furnace body 2 is 1400 ° C. In this figure, t0 to t1 indicate the time required for the wire tip to reach the slag surface from the furnace top, and t1 to t2 indicate the time required for the wire tip to reach the slag surface to the metal surface. Therefore, when the time point of the voltage change of the AC voltmeter 15 is converted from the feed amount of the wire 10, the position of the slag surface of the molten slag layer S in the furnace main body 2 (the distance from the furnace top) and the metal of the molten metal layer M The position of the surface (distance from the furnace top) is known. For example, as shown in FIG.
Assuming that 5 mm / s, t0 to t1 is 8 seconds, so the distance from the furnace top to the slag surface is 348 mm, and t1 to t2 is 10 seconds, so the distance from the slag surface to the metal surface, that is, the depth of the slag water is 448 mm. I understand.

In the above embodiment, an AC voltage is applied between the electrodes 4 and 4, and the AC voltage is detected using the AC voltmeter 15. However, a DC voltage is applied between the electrodes 4 and 4. In this case, since the DC voltage changes in the same manner as the AC voltage from when the wire 10 reaches the slag surface of the molten slag layer S to the metal surface of the molten metal layer M, a DC voltmeter may be used. Of course, the same operation and effect can be obtained.

[0013]

As described above, according to the present invention, a metal wire is fed from a furnace top of an incineration ash melting furnace to a terminal plate provided on the furnace bottom at a predetermined feed rate, Measure the voltage change between the wire and the terminal plate caused by the current flowing between the electrodes in the molten slag during the wire feeding, and based on the wire feed amount and the voltage change, the slag surface from the furnace top and Since the position of the metal surface was calculated and found,
This has the effect that the position of the slag surface of the molten slag layer and the position of the metal surface of the molten metal layer in the incineration ash melting furnace whose upper part is closed can be easily known.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a molten metal surface depth measuring device of an incineration ash melting furnace according to one embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement of electrodes and wires of an incineration ash melting furnace.

FIG. 3 is a waveform diagram of a voltmeter of the measuring device when the molten slag is 1400 ° C.

FIG. 4 is a graph showing a relationship between a voltage change of a voltmeter of the measuring device and a wire feeding time.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Incineration ash melting furnace 4 Electrode 6 Terminal plate 10 Wire 11 Wire feeder 14 Encoder 15 AC voltmeter 16 Calculation means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-37479 (JP, A) JP-A-51-116903 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01F 23/24

Claims (2)

(57) [Claims] 1. A method for measuring the depth of a molten metal surface of an incineration ash melting furnace in which an upper portion is sealed and a plurality of electrodes filled in the furnace are heated by electric resistance to melt the incineration ash charged into the furnace. A metal wire is fed from the furnace top to a terminal plate provided on the furnace bottom at a predetermined feed rate, and flows between the electrodes for electric resistance heating in the molten slag during the wire feed. The change in voltage between the wire and the terminal plate provided on the furnace bottom caused by the current is measured, and the feed amount of the wire and the voltage become zero.
Time to change from V and time to change to 0V
A method for measuring the molten metal surface depth of an incineration ash melting furnace, wherein the positions of a slag surface and a metal surface from the furnace top are calculated and obtained based on the interval. 2. An incineration ash melting furnace for melting incineration ash charged into the furnace by electric resistance heating of a plurality of electrodes filled in the furnace from the top to the bottom of the furnace. A wire feeder that feeds a metal wire at a predetermined feed amount toward the terminal plate, and an encoder that measures the feed amount of the wire sent by the wire feeder,
Caused by the current flowing between the electrodes for electrical resistance heating
Change a voltage meter for measuring the voltage, the time and 0V for the voltage of the encoder has measured the wire feed amount and a voltmeter measuring changes from 0V between the wire and the terminal plate that
And a calculating means for calculating the positions of the slag surface and the metal surface from the furnace top based on the time required to perform the process.